Sen. Thad Cochran talks to supporters June 24 at his runoff election victory party in Jackson, Miss., after winning the GOP nomination for Senate. (Rogelio V. Solis/AP)

The head of the Missouri Republican Party on Tuesday asked Republican National Committee Chairman Reince Priebus to appoint a task force to investigate what he called "racially divisive ads and robocalls" that were critical of state Sen. Chris McDaniel in the Republican runoff for U.S. Senate in Mississippi, marking the the latest instance of lingering intra-party discord following Sen. Thad Cochran's narrow win over McDaniel last month.

Missouri GOP Chairman Ed Martin e-mailed letters to Priebus and RNC members Tuesday afternoon expressing concerns over ads reported by Britain's Daily Mail newspaper that sought to link McDaniel to a Ku Klux Klan ally, suggested that the tea party has "racist" ideas and warned that a vote for McDaniel could mean losing food stamps and other government programs.

Martin's concerns came a day after Sen. Ted Cruz (R-Tex.) slammed the "D.C. machine" for "racially charged false attacks" against McDaniel. And they arrived as McDaniel's campaign was gearing up to challenge the results of the election, which were certified Monday.

"Last week, the Clarion-Ledger was able to tie McDaniel's campaign to an ally of the Ku Klux Klan," said the narrator of one of the ads reported by the Daily Mail, an apparent reference to a newspaper report about a McDaniel supporter named Carl Ford, who reportedly had Klan ties. The same narrator said in another commercial that "if the tea party with their racist ideas win, we will be set back to the '50s and '60s."

Martin, who said he was neutral during the primary and runoff, said his concern is that Republican National Committee member Henry Barbour could be partially responsible for the ads. The Daily Mail report suggested Barbour, who ran a pro-Cochran super PAC, could have ties to the group that ran the ads, which called itself "Citizens for Progress." The group has no record at the Federal Election Commission.

"We cannot object to the Left smearing conservatives with such labels if we do not rebuke those on our side who sink to such tactics," Martin writes in his letter obtained by The Washington Post.

In an interview, Barbour said his group ran no racially charged radio ads and he has no idea who sponsored the commercials cited in the Daily Mail report, which he has not even heard.

"We ran no radio ads that had anything to do with the KKK or race, or anything like that," said Barbour.

Martin asked Priebus to "appoint a special committee of RNC members to investigate this matter and report to us at our August 7th Members meeting before the August 8th general RNC meeting." Martin said in a telephone interview that he already received a response from one RNC member volunteering to join the special committee.

A Republican National Committee spokeswoman did not immediately respond to requests for comment.

Cochran and his allies courted Democratic voters, including many African Americans, during the runoff campaign. The strategy apparently worked, based on a Washington Post analysis which showed that in 24 counties with a majority black population, turnout increased an average of 40 percent over the primary. In the state’s 58 other counties, the increase was 16 percent.

Cochran was certified as the winner of the June 24 runoff winner by the Mississippi Republican Party on Monday. But McDaniel's campaign signaled that it is moving toward challenging the results on allegations of voter fraud. A spokesman for McDaniel said the campaign would not present its evidence until it lodged its complaint with the state GOP.

Cochran's campaign said the certified results — which showed Cochran defeating McDaniel by 7,667 votes — demonstrate that he clearly won and McDaniel's complaints are without merit.

Below are Martin's complete letters to Priebus and members of the RNC.

Dear fellow RNC member,

Please see below and attached.

Over the past few days, I have reached out to many but not all of you about some of what Missouri Republicans were asking about re Mississippi especially about the racially divisive ads run in support of Senator Cochran.

Many of you gave me good advice, some were silent, and I got lots of input from Mississippi too. My purpose in this is for us - we the RNC - to lead and help find out exactly what happened and move past it. I consider this type of leadership central to our role as party leaders.

Some of my discussions were not easy with others being brought in via forwarded emails and some were contentious (with one exchange bordering on threatening) as folks want to move on. I mean this to be an RNC issue - that we sort out. But we cannot shy from the truth.

At this point, I am asking Reince to lead us - to appoint a committee of we RNC members to get to the bottom of the facts regarding the racially divisive ads and to report back to us for the August meeting. I have purposely left the membership of this committee up to Reince so that he can move quickly.

I do not mean for this to be hostile but I do mean this to be about truth-telling. I hope you will consider supporting my request.

Thanks.

All the best.

Ed

--------

Dear Chairman Priebus,

As you know, the situation in Mississippi following the Republican primary run-off is receiving national attention.

I have been particularly concerned about the racially divisive ads and robocalls that have been reported by the Daily Mail. Specifically, that reporting indicated that one of our RNC members was directly responsible for the racially divisive ads.

I have been asking some of my fellow RNC members for their input and advice. Many of us are unsure of all of the facts and seek more.

Specifically, if one of our own members helped finance ads or robocalls that tarred Tea Partiers as a group as racists, I am sure that most RNC members would find that deeply offensive, indeed unacceptable. We cannot object to the Left smearing conservatives with such labels if we do not rebuke those on our side who sink to such tactics.

At this time, I respectfully request that you appoint a special committee of RNC members to investigate this matter and report to us at our August 7th Members meeting before the August 8th general RNC meeting. This would give us time to address the issues and act if necessary.

Thank you for your prompt consideration of my request.

All the best.

s/

Ed Martin

Sean Sullivan has covered national politics for The Washington Post since 2012.

Karen Tumulty is a national political correspondent for The Washington Post, where she received the 2013 Toner Prize for Excellence in Political Reporting.

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